Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M159/00—Lubricating compositions characterised by the additive being of unknown or incompletely defined constitution
  • C10M159/12—Reaction products
  • C10M159/20—Reaction mixtures having an excess of neutralising base, e.g. so-called overbasic or highly basic products
  • C10M159/22—Reaction mixtures having an excess of neutralising base, e.g. so-called overbasic or highly basic products containing phenol radicals

Definitions

• This invention is directed to overbased alkylated alkyl salicylates which overbased products are suitable for use in lubricating oil compositions used in internal combustion engines.
• these additives impart water tolerance, thermal stability, detergency, compatibility and good oxidation performance in such lubricating oil compositions.
• Overbased alkylated salicylates are a class of lubricating oil detergents known to impart improved performance (detergency, water tolerance, thermal stability, antioxidancy) to lubricating oil compositions used for lubrication of internal combustion engines.
• Overbased salicylates are prepared by overbasing the corresponding alkylated salicylic acids which, in turn, are typically prepared by first alkylating phenol to form alkylphenol followed by carboxylation via the Kolbe-Schmitt reaction to provide for alkylated salicylic acid.
• the alkyl group is typically a long chain alkyl group of greater than about 14 carbon atoms so as to impart oil solubility.
• One method of circumventing this problem is to alkylate an alkyl salicylate (e.g., methyl salicylate) and then subject the resulting alkylated alkyl salicylate to hydrolysis so as to provide for the alkylated salicylic acid.
• alkyl salicylate e.g., methyl salicylate
• hydrolysis so as to provide for the alkylated salicylic acid.
• This latter synthetic scheme involves formation of an alkyl salicylate, alkylation of the alkyl salicylate to form an alkylated alkyl salicylate, followed by hydrolysis to form the alkylated salicylic acid. Hydrolysis of the alkylated alkyl salicylate to form alkylated salicylic acid was perceived necessary to later formation of overbased products since the carboxyl (-COOH) group was deemed to be an essential component during overbasing.
• overbased products are prepared by the addition of excess basic metal (i.e., greater than that required to neutralize all of the acidic species on the salicylic acid) optionally using carbon dioxide and it was considered that the carboxyl group played an essential role in the ability of the alkylated salicylic acid to incorporate excess basic metal and carbon dioxide presumably via chelation.
• excess basic metal i.e., greater than that required to neutralize all of the acidic species on the salicylic acid
• carbon dioxide it was considered that the carboxyl group played an essential role in the ability of the alkylated salicylic acid to incorporate excess basic metal and carbon dioxide presumably via chelation.
• This invention is directed, in part, to the discovery that alkylated alkyl salicylates can be overbased without hydrolysis of the ester functionality to provide for overbased lubricating oil additives suitable for use in lubricating oil compositions.
• This discovery is particularly surprising in view of the fact that the overbased products of this invention lack carboxyl (-COOH) functionality but, rather, possess an ester (-COOR) functionality (R being alkyl of from 1 to 6 carbon atoms).
• This invention is based, in part, on the discovery that alkylated alkyl salicylates can be directly overbased without hydrolysis of the ester and such overbased products provide for a new class of lubricating oil additives, which exhibit detergency, a source of alkaline reserve, etc. in the finished lubricating oil composition.
• a lubricating oil soluble, overbased alkylated alkyl salicylate additive composition having a TBN of from greater than 0 to about 300, wherein the alkylated alkyl salicylate prior to overbasing has the formula I shown below.
• a process for producing a lubricating oil soluble, overbased alkylated alkyl salicylate composition which process comprises:
• a further aspect of the present invention provides a lubricating oil composition
• a lubricating oil composition comprising an oil of lubricating viscosity and from 2 to 30 weight percent of an overbased alkylated alkyl salicylate additive composition having a TBN of from greater than 0 to about 300, according to the present invention.
• Total Base Number refers to the amount of base equivalent to milligrams of KOH in 1 gram of additive. Thus, higher TBN numbers reflect more alkaline products and therefore a greater alkalinity reserve.
• the Total Base Number for an additive composition is readily determined by ASTM test method number D2896 or other equivalent methods.
• alkaline earth metal or "Group II metal” means calcium, barium, magnesium, and strontium.
• the Group II metal is selected from the group consisting of calcium, magnesium, barium, and mixtures thereof. Most preferably, the Group II metal is calcium.
• alkaline earth metal base refers to basic alkaline earth metal materials suitable for use in preparing overbased alkylated alkyl salicylates and, include by way of example, alkaline earth metal oxides, hydroxides and C 1 to C 6 alkoxides.
• alkyl salicylates refers to compounds of the formula: wherein R is an alkyl group of from 1 to 6 carbon atoms. Preferably, R is an alkyl group of from 1 to 3 carbon atoms and most preferably R is methyl.
• alkylated alkyl salicylate refers to alkyl salicylates which have been alkylated with a long chain carbon feed which alkylated products can be represented by the formula: where R is as defined above; R' is an alkyl group of from 15 to 50 carbon atoms; and n is an integer of from 1 to 2 and is preferably 1. In a preferred embodiment, the amount of dialkylation in the product is maintained to about 5% or less.
• overbased alkylated alkyl salicylate compositions refers to compositions prepared by reacting an alkylated alkyl salicylate with an amount of alkaline earth metal base in excess of that necessary to neutralize the acidic species on the alkylated alkyl salicylate and optionally with carbon dioxide.
• overbased products are characterized as having a TBN of greater than 0 and no more than about 300.
• overbased alkylated alkyl salicylate compositions described herein can contain diluent and the term "overbased alkylated alkyl salicylate compositions" is meant to include compositions containing such diluent.
• such compositions are manufactured to contain some diluent and, after manufacture, the diluent can be removed, replaced or additional amounts of diluent can be added to provide for an additive composition preferably having from 0 to 40 weight percent diluent.
• these additive compositions contain concentrated amounts of the overbased alkylated alkyl salicylate of which only a small amount is added together with other additives to a lubricating oil so as to provide for a fully formulated lubricant composition suitable for use in an internal combustion engine.
• substantially straight-chain alkyl group means an alkyl group which is attached to the benzene ring of the alkyl salicylate through a secondary, tertiary or quaternary carbon atom and which contains minimal branching in the remainder of the carbon atoms of the alkyl group (i.e., less than 20% of the remaining carbon atoms are tertiary and/or quaternary carbon atoms in the molecular structure of the alkyl group).
• Suitable substantially straight-chain alkyl groups include, for example, 1-hexadecyl -[CH 2 (CH 2 ) 14 CH 3 ) (0% of the carbon atoms are tertiary or quaternary carbon atoms), 4-methyl-1-hexadecyl -[CH 2 (CH 2 ) 2 CHCH 3 (CH 2 ) 11 CH 3 ] ( ⁇ 7% of the carbons are branched), etc.
• the substantially straight-chain alkyl group contains less than 15% tertiary and/or quaternary carbon atoms in the remainder of the alkyl group; more preferably, less than 10%; still more preferably, less than 5%; and most preferably, the substantially straight-chain alkyl group contains no tertiary or quaternary carbon atoms in the remainder of the alkyl group.
• oil solubility means that the additive has a solubility of at least 50 grams per kilogram and preferably at least 100 grams per kilogram at 20°C in a base 10W40 lubricating oil.
• alkylated alkyl salicylate is overbased with an excess amount of an alkaline earth metal base (e.g., alkaline earth metal oxide, hydroxide or C 1 to C 6 alkoxide) and optionally with carbon dioxide.
• an alkaline earth metal base e.g., alkaline earth metal oxide, hydroxide or C 1 to C 6 alkoxide
• alkaline earth metal base is combined with the alkylated alkyl salicylate under conditions wherein the amount of such base employed is that which is in excess of that necessary to neutralize the acidic species on the alkylated alkyl salicylate and optionally carbon dioxide is also employed to further enhance the basicity of the overbased product.
• Such overbased products are characterized as having a TBN of greater than 0 and preferably no more than about 300.
• the reaction is preferably conducted in an inert diluent under conditions wherein the alkaline earth metal base is incorporated into the alkylated alkyl salicylate.
• the reaction is conducted at a temperature of from 20°C to 100°C and is preferably complete within a period of from 0.2 to 5 hours.
• the amount of alkylated alkyl salicylate employed is preferably from 5 to 50 weight percent based on the total of diluent and alkylated alkyl salicylate employed and more preferably from 15 to 50 weight percent.
• alkaline earth metal base is incorporated through the hydroxyl group of the salicylate and that the carbonyl group of the ester participates in facilitating this incorporation.
• the amount of alkaline earth metal base which can be practically incorporated into alkylated alkyl salicylate is generally limited to products having a TBN of greater than 0 and less than about 100 and preferably less than about 50. While such products are nevertheless overbased products, the preparation of products having a TBN of greater than about 100 requires the further use of carbon dioxide. Also, carbon dioxide can be employed but is not necessary in the preparation of overbased compositions having a TBN of from greater than 0 to 100.
• the amount of alkaline earth metal base employed is from 0.6 to 2.5 molar equivalents based on the amount of alkylated alkyl salicylate employed. At this range, the alkaline earth metal base is in excess over that which is necessary to neutralize all of the acidic species on the alkylate alkyl salicylate.
• the solids are generally removed by conventional means (i.e., filtration, centrifugation, etc.) and the inert diluent solvent can be removed by conventional means such as stripping under reduced pressure.
• the inert diluent is preferably 2-ethylhexanol and diluent oil but a mixture of an alkanol of from 1 to 3 carbon atoms and an aromatic solvent having a boiling point less than about 150°C can also be employed.
• the inert diluent is preferably a mixture of an alkanol of from 1 to 3 carbon atoms and an aromatic solvent having a boiling point of less than about 150°C.
• Suitable alcohols include methanol, ethanol, n-propanol and iso-propanol.
• Suitable aromatic solvents having a boiling point of less than about 150°C include, by way of example, benzene, toluene, xylene, chlorobenzene and the like.
• the diluent preferably comprises from 5 to 30 weight percent of the alkanol of from 1 to 3 carbon atoms and from 95 to 70 weight percent of the aromatic solvent.
• a particularly preferred diluent is a mixture methanol and toluene preferably at a weight ratio of 20 to 80.
• lubricating oil base stock Other components can be included in the diluent such as lubricating oil base stock.
• the diluent does not contain a lubricating oil base stock and, after reaction completion, substantially all diluent is stripped from the overbased product to provide for a fluid product having a viscosity of less than about 1000 cSt at 100°C and preferably less than 500 cSt at 100°C.
• lubricating oil base stock is included during preparation of the overbased product and, after product preparation, the alkanol and aromatic solvent are removed by stripping.
• reaction is conducted in the absence of lubricating oil base stock and, after product preparation, the base stock is added either before or after the alkanol and aromatic solvent are removed by stripping.
• the resulting composition comprises a concentrate of the overbased alkylated alkyl salicylate in a base stock which is suitable for use in directly formulating a lubricating oil composition.
• the amount of lubricating oil base stock included in the concentrate comprises from 5 to 95 weight percent base stock and from 95 to 5 weight percent overbased alkylated alkyl salicylate.
• alkylated alkyl salicylates used in the preparation of overbased alkylated alkyl salicylates can be prepared by methods known in the art such as that described in Deutsche Patentschrift DD 269 619 and DD 272,065 as well as Japanese Patent Application No. 54/160335 which methods employ an excess of alkyl salicylate to the alkylating agent (e.g., olefin) or an excess of alkylating agent to the alkyl salicylate.
• the alkylated alkyl salicylates are preferably prepared by the methods described in the aforementioned U.S. Patent Application Serial No. 08/ 172 , 544 filed concurrently herewith as Attorney Docket No. 005950-367 and entitled "ALKYLATION OF ALKYL SALICYLATE USING A LONG CHAIN CARBON FEED" and which are further described in Example 2 below.
• the alkylated alkyl salicylate is alkylated with substantially straight-chain olefins.
• Particularly preferred alkylating olefins include substantially straight-chain C 20 -C 28 olefins, substantially straight-chain C 20 -C 24 olefins, and substantially straight-chain C 24 -C 28 olefins.
• oil-soluble, overbased alkylated alkyl salicylate compositions described above are useful lubricating oil additives imparting detergency and dispersancy properties when added to the lubricating oil employed in the crank case of an internal combustion engine as well as an alkaline reserve which is essential to neutralize acidic combustion products produced during engine operation.
• Such lubricating oil compositions are useful in diesel engines, gasoline engines as well as in marine engines.
• the amount of oil-soluble, neutral and low overbased alkyl methyl salicylate added to the lubricating oil composition ranges from 0.5 to 40 weight percent of the total lubricant composition although preferably from 2 to 30 weight percent of the total lubricant composition.
• Such lubricating oil compositions employ a finished lubricating oil which may be single or multigrade.
• Multigrade lubricating oils are prepared by adding viscosity index (VI) improvers.
• VI viscosity index
• Typical viscosity index improvers are polyalkyl methacrylates, ethylene, propylene copolymers, styrene-diene copolymers, and the like.
• the lubricating oils used in such compositions may be mineral oils or synthetic oils of viscosity suitable for use in the crank case of an internal combustion engine such as gasoline engines and diesel engines which include marine engines.
• Crank case lubricating oils ordinarily have a viscosity of about 1300 cSt at 0°F to 24 cSt at 210°F (99°C).
• the lubricating oils may be derived from synthetic or natural sources.
• Mineral oils for use as the base oil in the invention includes paraffinic, naphthenic and other oils that are ordinarily used in lubricating oil compositions.
• Synthetic oils include both hydrocarbon synthetic oils and synthetic esters.
• Useful synthetic hydrocarbon oils include liquid polymers of ⁇ -olefins having the proper viscosity.
• the hydrogenated liquid oligomers of C 6 to C 12 alpha olefins such as 1-decene trimer.
• alkylbenzenes of proper viscosity such as didodecyl benzene
• useful synthetic esters include esters of both monocarboxylic acids and polycarboxylic acids as well as monohydroxy alkenols and polyols. Typical examples are didodecyl adipate, pentaerythritol tetracaproate, di-2-ethylhexyl adipate, dilaurylsebacate and the like.
• Complex esters prepared from mixtures of mono and dicarboxylic acid and mono and dihydroxy alkanols can also be used.
• Blends of hydrocarbon oils with synthetic oils are also useful. For example, blends of 10 to 25 weight percent hydrogenated 1-decene trimer with 75 to 90 weight percent 150 SUS (100°F) mineral oil gives an excellent lubricating oil base.
• additives which may be present in the formulation include rust inhibitors, foam inhibitors, corrosion inhibitors, metal deactivators, pour point depressants, anti-oxidants, and a variety of other well-known additives.
• Methyl salicylate (from Aldrich Chemical Company, Milwaukee, Wisconsin, USA) was alkylated with a C 20 -C 24 olefin carbon feed at a molar ratio of 5:1 of methyl salicylate to carbon feed.
• 1802.6 grams of a C 20 -C 24 olefin fraction (available from Chevron Chemical Company, San Ramon, California, USA), was charged to a 5 liter, four-neck oven dry flask. 2457.5 grams of methyl salicylate followed by 591.3 grams of AMBERLYST® 36 sulfonic acid resin (available from Rohm and Haas, Philadelphia, Pennsylvania, USA) were next charged to the flask. The flask was then equipped with a stirrer, temperature probe with controller, reflux condenser and a nitrogen blanket.
• the reaction mixture was heated to a temperature of 125°C over a period of 50 minutes and held at that temperature for approximately 48 hours. After 48 hours, about 94.2% conversion of the methyl salicylate to alkyl methyl salicylate had occurred.
• the reaction mixture was cooled with stirring overnight to a temperature of about 50°C.
• the crude alkyl methyl salicylate was removed from the reaction flask by using a gas dispersion tube and pulling it into a four liter flask under vacuum.
• the catalyst remained in the reaction flask.
• Product remaining on the catalyst was removed by rinsing the contents, of the flask with approximately 400 ml portions of toluene while stirring, followed by pulling the toluene and crude product into a two liter flask through a gas dispersion tube under vacuum. This rinsing/pulling procedure was repeated additional three times.
• the toluene recovered in this procedure was stripped on a rotovap at a temperature of approximately 95°C to 100°C under vacuum ( ⁇ 25 mm of Hg vacuum) and the resulting stripped product was combined with the recovered crude alkylated methyl salicylate.
• the combined crude alkylated methyl salicylate was then stripped at a temperature of about 130°C at a pressure of approximately 1 to 10 mm of mercury. Further stripping was conducted at a temperature of about 185°C to 191°C at a pressure of approximately 1 to 10 mm of mercury. Product analysis indicated that about 94.7 weight percent of the methyl salicylate was alkylated.
• Methyl salicylate commercially obtained from Aldrich Chemical Company, Milwaukee, Wisconsin, USA was alkylated using a long chain carbon feed.
• 617.9 grams (2.0 moles) of a C 20 -C 24 alpha olefin fraction (available from Chevron Chemical Company, San Ramon, California, USA) was charged to a 2 liter, three-neck oven dry flask.
• the flask was then equipped with a stirrer, temperature probe with controller, reflux condenser and a nitrogen blanket.
• Alky methyl salicylate produced in the manner similar to either Example 1 or 2 above is overbased with an excess of calcium hydroxide.
• 100 grams of C 20 -C 24 alkylated methyl salicylate is combined into approximately 500 ml of 2-ethylhexanol at room temperature.
• About 20 grams of lime are added to the solution and the solution is maintained at about 30°C for about 2 hours.
• the 2-ethylhexanol diluent is removed by stripping to provide for an overbased alkylated alkyl salicylate having a TBN of greater then zero and less than about 100.
• the system Upon completion of the carbonation step, the system was heated to 93°C over a 2 hour period and then heated to 132°C over a 30 minute period. At this point, 155 grams of diluent oil, CitCon 100N (trade mark), was added and the system heated to 204°C over 1.5 hours under vacuum to strip of the xylene. The resulting solution was then filtered over Celite" (diatomaceous earth available from Manville Corporation) so as to provide an overbased carbon dioxide containing alkyl methyl salicylate additive composition having a TBN of about 182 and a viscosity of 100°C of about 19 cSt.
• Celite diatomaceous earth available from Manville Corporation
• Overbased Alkylated alkyl salicylate prepared in Example 4 above was tested for dispersancy in the following dispersion test.
• the dispersant ability of the formulated lubricating oil composition is obtained by conducting chromatography on paper of a mixture of the lubricating oil composition to be tested and an artificial sludge under the following conditions: Spot No. 1 Ambient temperature without water Spot No. 2 10 minutes at 200°C without water Spot No. 3 10 minutes at 250°C without water Spot No. 4 Ambient temperature with 1% water Spot No. 5 10 minutes at 200°C with 1% water Spot No. 6 10 minutes at 250°C with 1% water
• the spots are rated after 48 hours. For each spot, the diameters of diffusion of soot (d) and of the oil (D) are measured and the ratio d D X 100 is calculated. The dispersancy of the oil over a variety of conditions is obtained from the sum of the six spot ratings. Oils having values of greater than about 250 are considered to have dispersant properties and are compared to reference oils, i.e., an oil having 23.4 weight percent of commercially available salicylate under otherwise identical parameters.
• the lubricating oil composition was prepared by combining 22 weight percent of an overbased alkylated alkyl salicylate similar to that of Example 4 above, 0.67 weight percent of a zinc dithiophosphate and 1.60 weight percent of an alkenyl succinimide to a SAE 30 oil.
• the resulting composition has 1.505 weight percent calcium, 0.080 weight percent zinc; 0.050 weight percent phosphorus; 0.03 weight percent nitrogen; a TBN of about 40.2; and a viscosity of 100°C of 11.8 cSt.
• test lubricating oil composition (20 ⁇ l of each but done in duplicate) are syringed onto 2 separate sheets of paper using a 100 ⁇ l syringe.
• the heated samples are first incubated in a heating bath at the indicated temperature for 10 minutes before application.
• the papers are stored in the horizontal position for 48 hours at a temperature of from about 20° to about 25°C. Storage is conducted under conditions to shelter the papers from dust.
• the spots should be circular and the zone of dispersion of the soot (d) as well as the zone of the dispersion of the oil (D) are measured.
• the sum of the six values of d/D x 100 should be at least 250. In the present case, the sum was 312. This indicates that the salicylates of this invention possess dispersant properties. Additionally, comparison to reference oil indicates similar properties, i.e., the sum of these 6 spots for the reference oil was 332.
• Overbased alkylated alkyl salicylate prepared in Example 4 was tested for its hydrolytic stability.
• the test comprises preparing a formulated lubricating oil composition wherein the TBN is derived primarily from the overbased alkylated alkyl salicylate composition.
• the tested lubricant compositions were formulated with 1 weight percent of a succinimide dispersant and 8 mmoles of a ZnDTP containing secondary alkyl groups in a base stock which was additionally formulated with 22 weight percent of the alkylated alkyl salicylate so as to provide for a TBN of about 40.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Organic Chemistry (AREA)
• Lubricants (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)

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• 1993
  • 1993-12-23 US US08/173,192 patent/US5415792A/en not_active Expired - Fee Related
• 1994
  • 1994-12-21 CA CA002153664A patent/CA2153664A1/en not_active Abandoned
  • 1994-12-21 DE DE69427080T patent/DE69427080T2/de not_active Expired - Fee Related
  • 1994-12-21 JP JP7517591A patent/JPH08507103A/ja not_active Abandoned
  • 1994-12-21 AU AU14426/95A patent/AU690194B2/en not_active Ceased
  • 1994-12-21 WO PCT/US1994/014763 patent/WO1995017486A1/en active IP Right Grant
  • 1994-12-21 EP EP95906066A patent/EP0686185B1/en not_active Expired - Lifetime
  • 1994-12-21 SG SG1996007108A patent/SG54278A1/en unknown

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